A conventional air-conditioning apparatus that uses a refrigeration cycle, such as a heat pump cycle, includes a refrigerant circuit through which refrigerant flows. In the refrigerant circuit, a heat source unit including a compressor and a heat-source-side heat exchanger is connected by pipes to an indoor unit including an expansion valve and a load-side heat exchanger. The air-conditioning apparatus performs air conditioning while changing the pressure, temperature, and other factor of refrigerant flowing through the refrigerant circuit by removing heat from or transferring heat to air in an air-conditioned space, which is a target of heat exchange, when the refrigerant evaporates or condenses in the load-side heat exchanger. Also suggested is an air-conditioning apparatus including a heat source unit, a plurality of indoor units, and a relay unit that distributes refrigerant supplied from the heat source unit to the plurality of indoor units. In such an air-conditioning apparatus, a simultaneous cooling and heating operation is performed in which necessity of a cooling operation or a heating operation is automatically determined for each of the plurality of indoor units depending on a temperature set by a remote control or other related component supplied with to the indoor unit, an ambient temperature of the indoor unit, and other temperatures, and a cooling operation or a heating operation is performed in each indoor unit.
As an air-conditioning apparatus that performs a simultaneous cooling and heating operation, Patent Literature 1 discloses an air-conditioning apparatus including a heat source unit in which a heat-source-side heat exchanger and a fourth flow control device are connected in series to each other and the heat-source-side heat exchanger and a switching valve are connected in parallel to each other. The air-conditioning apparatus disclosed in Patent Literature 1 further includes a gas-liquid separator that connects a point between the heat-source-side heat exchanger and the fourth flow control device, an accumulator, and a high-pressure pipe to each other, and a fifth flow control device disposed between the gas-liquid separator and the accumulator. According to Patent Literature 1, in the case of a cooling main operation in which the heat-source-side heat exchanger acts as a condenser, the condensation ability of the heat-source-side heat exchanger is controlled by controlling the fourth flow control device and the switching valve depending on a ratio of a cooling operation capacity to a heating operation capacity of the plurality of indoor units. In addition, according to Patent Literature 1, in the case of a heating main operation in which the heat-source-side heat exchanger acts as an evaporator, the evaporation ability of the heat-source-side heat exchanger is controlled by controlling the fifth flow control device depending on a ratio of a cooling operation capacity to a heating operation capacity of the plurality of indoor units.